Vertical MIM capacitor

ABSTRACT

Vertical metal-insulator-metal (MIM) capacitors include a metal conductor including a sidewall; a high k dielectric layer on the sidewall of the metal conductor; and a vertically oriented metal layer on the high k dielectric layer. Also disclosed are methods for fabricating the vertical MIM capacitor, wherein a single patterning/mask process can used to fabricate the vertical MIM capacitor structure.

BACKGROUND

The present invention generally relates to semiconductor integratedcircuits, and more particularly, to the structure and formation ofvertical metal-insulator-metal capacitors in the semiconductorintegrated circuits.

Various capacitive structures are used as electronic elements inintegrated circuits such as radio frequency integrated circuits (RFIC),and monolithic microwave integrated circuits (MMIC). Such capacitivestructures include, for example, metal-oxide-semiconductor (MOS)capacitors, p-n junction capacitors and metal-insulator-metal (MIM)capacitors. A MIM capacitor typically includes an insulating layer, suchas a PECVD dielectric, disposed between lower and upper electrodes. MIMcapacitors are typically used to store a charge in a variety ofsemiconductor devices, such as mixed signal and analog products. Forsome applications, MIM capacitors can provide certain advantages overMOS and p-n junction capacitors because the frequency characteristics ofMOS and p-n junction capacitors can be restricted as a result ofdepletion layers that form in the semiconductor electrodes. Furthermore,MIM capacitors are formed in the metal interconnect layers, therebyreducing CMOS transistor process integration interactions orcomplications.

SUMMARY

In one or more embodiments, a vertical metal-insulator-metal (MIM)capacitor includes a metal conductor including a vertically orientedsidewall. A high k dielectric layer is on the vertically orientedsidewall of the metal conductor; and a vertically oriented metal layeris on the high k dielectric layer. The metal conductor, the high kdielectric layer on the metal conductor sidewall, and the verticallyoriented metal layer on the high k dielectric layer define the verticalMIM capacitor.

In one or more embodiments, a process for forming a verticalmetal-insulator-metal capacitor includes providing a semiconductorsubstrate having a patterned insulator layer including a metal conductorformed in the patterned insulator layer, wherein a top surface of thepatterned insulator layer is coplanar to a top surface of the metalconductor. A metal cap layer is selectively deposited onto the topsurface of the metal conductor. The patterned insulator layersurrounding the metal conductor is removed. A high k dielectric materialis selectively deposited onto a sidewall of the metal conductor. A metalplate layer is conformally deposited onto the semiconductor substrate. Asecond insulator layer is deposited onto the semiconductor substrate.The semiconductor substrate is planarized to the top surface of themetal conductor, wherein the metal conductor sidewall, the high kdielectric material and the metal plate layer are vertically orientedand define the vertical MIM capacitor.

In one or more embodiments, a process for forming a verticalmetal-insulator-metal capacitor includes providing a semiconductorsubstrate having a patterned insulator layer including a metal conductorformed in the patterned insulator layer, wherein a top surface of thepatterned insulator layer is coplanar to a top surface of the metalconductor. A dielectric cap layer is blanket deposited onto the coplanartop surfaces of the metal conductor and the patterned insulator layer.The dielectric cap layer is patterned to expose the top surface of thepatterned insulator layer. The exposed patterned insulator layersurrounding the metal conductor is removed. A high k dielectric materialis selectively depositing onto a sidewall of the metal conductor. Ametal plate layer is conformally deposited onto the semiconductorsubstrate. A second insulator layer is deposited onto the semiconductorsubstrate. The semiconductor substrate is planarized to the top surfaceof the metal conductor, wherein the metal conductor sidewall, the high kdielectric material and the metal plate layer are vertically orientedand define the vertical MIM capacitor.

Additional features and advantages are realized through the techniquesof the present invention. Other embodiments and aspects of the inventionare described in detail herein and are considered a part of the claimedinvention. For a better understanding of the invention with advantagesand features, refer to the description and to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter that is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other objects, features, andadvantages of the invention are apparent from the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 depicts a schematic cross-sectional view illustrating asemiconductor structure including a metal conductor in an insulatinglayer subsequent to planarization in accordance with one or moreembodiments;

FIG. 2 depicts a schematic cross-sectional view illustrating thesemiconductor structure after selective deposition of a cap layer on atop surface of the metal conductor in accordance with one or moreembodiments;

FIG. 3 depicts a schematic cross-sectional view illustrating thesemiconductor structure after removal of the insulating layer abuttingthe metal conductor in accordance with one or more embodiments;

FIG. 4 depicts a schematic cross-sectional view illustrating thesemiconductor structure after selective deposition of a high kdielectric on a sidewall of the metal conductor in accordance with oneor more embodiments;

FIG. 5 depicts a schematic cross-sectional view illustrating thesemiconductor structure after conformal deposition of a metal platelayer onto the structure in accordance with one or more embodiments;

FIG. 6 depicts a schematic cross-sectional view illustrating thesemiconductor structure after interlayer dielectric deposition onto thestructure in accordance with one or more embodiments;

FIG. 7 depicts a schematic cross-sectional view illustrating thesemiconductor structure after planarization to the metal conductor,thereby defining the vertical MIM capacitor in accordance with one ormore embodiments; and

FIG. 8 depicts a schematic cross-sectional view illustrating thesemiconductor structure including the vertical MIM capacitor afterinterconnection of the metal conductor with an interconnect structure inaccordance with one or more embodiments;

The detailed description explains the embodiments of the invention,together with advantages and features, by way of example with referenceto the drawings.

DETAILED DESCRIPTION

Detailed embodiments of the structures of the present invention aredescribed herein. However, it is to be understood that the embodimentsdescribed herein are merely illustrative of the structures that can beembodied in various forms. In addition, each of the examples given inconnection with the various embodiments of the invention is intended tobe illustrative, and not restrictive. Further, the figures are notnecessarily to scale, some features can be exaggerated to show detailsof particular components. Therefore, specific structural and functionaldetails described herein are not to be interpreted as limiting, butmerely as a representative basis for teaching one skilled in the art tovariously employ the methods and structures of the present description.For the purposes of the description hereinafter, the terms “upper”,“lower”, “top”, “bottom”, “left,” and “right,” and derivatives thereofshall relate to the described structures, as they are oriented in thedrawing figures.

The same numbers in the various figures can refer to the same structuralcomponent or part thereof. The following definitions and abbreviationsare to be used for the interpretation of the claims and thespecification. As used herein, the terms “comprises,” “comprising,”“includes,” “including,” “has,” “having,” “contains” or “containing,” orany other variation thereof, are intended to cover a non-exclusiveinclusion. For example, an article or apparatus that comprises a list ofelements is not necessarily limited to only those elements but caninclude other elements not expressly listed or inherent to such articleor apparatus.

As used herein, the articles “a” and “an” preceding an element orcomponent are intended to be nonrestrictive regarding the number ofinstances (i.e. occurrences) of the element or component. Therefore, “a”or “an” should be read to include one or at least one, and the singularword form of the element or component also includes the plural unlessthe number is obviously meant to be singular.

As used herein, the terms “invention” or “present invention” arenon-limiting terms and not intended to refer to any single aspect of theparticular invention but encompass all possible aspects as described inthe specification and the claims.

As previously noted herein, the MIM capacitor is one of the most commonelectrical components used in almost every electrical device. Prior artMIM capacitors are manufactured in the back end of line (BEOL) and arehorizontally oriented. Most MIM capacitors are fabricated by forming thebottom capacitive plate in a first or subsequent horizontalmetallization layer of a semiconductor wafer. A second mask, pattern andetch step is required to form the top capacitive plate. Alternatively,MIM capacitors are formed between horizontal metallization layers in theBEOL in additional horizontal layers, with each plate requiring aseparate pattern and etch level.

One of the problems associated with MIM capacitor fabrication is thehigh cost given that each plate in the capacitor requires a separatepattern and etch level. Moreover, as devices continue to scale to evershrinking dimensions, there is a limited area within which to fabricatethe MIM capacitor not to mention the accompanying performance issues.

The present invention generally provides semiconductor structuresincluding vertical MIM capacitors, which overcomes some of the problemsassociated with horizontal MIM capacitors. The vertical MIM capacitorstructures and processes generally include a single patterning and maskstep to create the structure for the device.

Reference is now made to FIGS. 1-8, which are pictorial representations(through cross sectional views) depicting the basic processing steps andthe resulting semiconductor structure employed in one or moreembodiments of the present invention. Specifically, the inventive methodbegins with providing a post planarized semiconductor structure 10including a metal conductor 12, e.g., a conductive metal line, in apatterned insulator layer 14, which are formed on an underlying caplayer 16 as shown in FIG. 1. A metal liner 18 is intermediate the metaland the insulator layer 14, which can prevent the metal element 12 fromdiffusing into the insulator layer 14.

As shown, the top surface is substantially planar, which is generallyperformed to remove any metal overburden that typically results upondeposited of the metal into the patterned insulating layer. For example,the surface can be planarized using an electropolishing process. In anelectropolishing process small amounts of metal are etched from themetal by electroetch or electrochemical etching to provide a metalinterconnect having a top surface 20 generally coplanar to the topsurface of the insulating layer 14. Such a structure is often referredto as a recessed structure. In another embodiment, the planar surface isformed by chemical-mechanical-polishing (CMP), using a non-selectiveslurry composition. The slurry composition contains a silica abrasivematerial, which removes the different metal layers at substantially thesame rate. Alternatively, a planar surface can be formed by anon-selective plasma etching process. The plasma etching process caninclude additional planarizing layers deposited onto copper layer. Forexample, a layer of photoresist can be deposited onto copper layer priorto performing the non-selective etch process.

The metal level 12 is not intended to be limited and can be copper,aluminum, tungsten, ruthenium, iridium, rhodium, cobalt, or mixturesthereof. The metal can be formed by CVD, sputtering, electrochemicaldeposition or like processes. For example, the deposition of copper canproceed by electrochemical deposition such as electroplating orelectroless plating. Examples of suitable copper electroplatingcompositions are described in U.S. Pat. No. 6,911,229 assigned toInternational Business Machines Corporation, the entire description ofwhich is incorporated by reference in its entirety.

The metal liner 18 is not intended to be limited and can be titanium,tantalum, tantalum nitride or titanium nitride are often selected assuitable materials for forming the metal liner. The presence of themetal liner insures that the metal, participating in the interdiffusionduring subsequent annealing processes, will not further diffuse intounderlying dielectric layers.

The insulator layer 14 can be one of a number of different dielectricmaterials commonly used in integrated circuit fabrication. For example,dielectric layer 14 can be silicon dioxide, silicon nitride, siliconcarbide, or a doped glass layer, such as phosphorus silicate glass,boron silicate glass, and the like. In other embodiments, the dielectriclayer can be a low k dielectric layer, wherein low k generally refers tomaterials having a dielectric constant less than silicon dioxide.Exemplary low k dielectric materials include, without limitation, SiLK®from Dow Chemical, Coral® from Novellus, Black Diamond® from AppliedMaterials, and spin on dielectrics can be used. Coral® can be describedgenerically as a SiCOH dielectric. Depending upon the particulardielectric material, dielectric layer 14 can be formed by chemical vapordeposition deposited (CVD), plasma enhanced chemical vapor deposition(PECVD), atmospheric deposition as well as spin on techniques. In one ormore embodiments, dielectric layer 12 is a chemical vapor depositedmaterial, such as silicon dioxide or silicon nitride, which has beendeposited over a planarized dielectric layer.

Once the insulator layer 14 has been deposited, openings such as trenchand/or via features are photolithographically patterned into theinsulator layer 12. Photolithography can include forming a photoresist(not shown) onto at least the dielectric surfaces where openings aredesired, exposing the photoresist to a pattern of activating radiation,and then developing the exposed photoresist with a resist developer toprovide a patterned photoresist. At least one etch process can beemployed to transfer the pattern from the patterned photoresist into theinsulator layer 14 and form the opening. The etching process can be adry etch (e.g., reactive ion etching, plasma etching, ion beam etching,or laser ablation) and/or a wet chemical etch (e.g., potassium hydroxide(KOH)). After transferring the pattern, the patterned photoresist isremoved utilizing resist stripping processes, for example, ashing.

In FIG. 2, a capping layer 20 is selectively deposited onto the metal.The cap protects the underlying metal 12 from oxidation, humidity, andcontamination during formation of the interconnect structure and/or thenext metal level(s) on the semiconductor structure 10. Additionally,capping layer serves to prevent undesirable diffusion of the underlyingmetal conductor 12 into insulating layer 14.

In one or more embodiments, the capping layer can be a metal such ascobalt, tungsten, ruthenium or the like. The metal capping layer can beselectively deposited using chemical vapor deposition, atomic layerdeposition, electroless, or the like.

Optionally, instead of selective deposition, a cap formed of either adielectric or a metallic material can be first blanket deposited (notshown) onto the planar surface, and then follow with a patterningprocess to create a structure similar to FIG. 2. Suitable dielectricmaterials include, but are not limited to, silicon nitride, siliconcarbide, silicon oxycarbide, hydrogenated silicon carbide, silicondioxide, organosilicate glass, Si(N, H) and other low-k dielectrics.Suitable metallic materials include, but are not limited to, Ta, W, Jr,Rh, Co, Ru, Ni, Al, mixtures, thereof, or the like. The thickness of thecap 20 can be between 1 Angstrom and 1000 Angstroms or more. In one ormore embodiments, the thickness of the cap is 50 Angstroms to 500Angstroms, and in still one or more other embodiments, the thickness ofthe titanium nitride cap layer is 100 to 400 Angstroms.

In FIG. 3, the insulating layer 14 is selectively removed to the capmlayer 16 by a wet etch process. The term “wet etching” generally refersto application of a chemical solution. This can be a time controlled dipin the etch solution. Suitable etch solutions include HNO₃, HCL, H₂SO₄,HF or combinations thereof. Prior to wet etching, the dielectricmaterial is first damaged such as by a plasma treatment containing H₂,He, N₂, NH₃, O₂, or other chemicals. Removal of the dielectric materialprovides the semiconductor substrate 10 with the metal 12, the capthereon, and the liner 18 about the sidewalls of the metal.

In FIG. 4, a high k dielectric layer 22 is selectively deposited ontothe liner 18. As used herein, the term “high k” generally refers tomaterials having a dielectric constant greater than silicon dioxide. Thehigh k dielectric is not intended to be limited and can be deposited bychemical vapor deposition, atomic layer deposition or the like.

Exemplary high k dielectric materials include tantalum oxide (Ta₂O₅,TaO₂), barium strontium titanate (BST), strontium titanate (ST), bariumtitanate (BT), lead zirconium titanate (PZT), silicon carbide, siliconoxynitride, silicon nitride, zirconium oxide, aluminum oxide, hafniumoxide, strontium bismuth tantalate (SBT) or the like. Such materialseffectively possess dielectric constants significantly greater thanconventional dielectrics, wherein k equals 3.9 for silicon dioxide, thedielectric constants of these high k materials can range from about 10to as high as about 800. Using such materials enables the creation ofmuch smaller and simpler capacitor structures for a given stored chargerequirement, enabling the packing density dictated by future generationcircuit design. By way of example, TaOxNy can be selectively depositedono the sidewalls of the metal 12 and thermally treated to convert thefilm to a TaOx high k dielectric material. As will be discussed ingreater detail below, any high k dielectric material deposited onto thecap 20 is of no consequence as it will later be removed. The thicknesscan range from between 1 Angstrom and 1000 Angstroms or more. In one ormore embodiments, the thickness of the high k dielectric material is 10Angstroms to 500 Angstroms, and in still one or more other embodiments,the thickness of the high k layer is 50 to 100 Angstroms

Referring now to FIG. 5, a conformal metal plate layer 24 is thendeposited onto the substrate 10. The conformal metal plate layer 24 canbe deposited by plasma vapor deposition, chemical vapor deposition,atomic layer deposition, or the like. Suitable metals for forming themetal layer include, without limitation, copper, tungsten, aluminum,tantalum, titanium, cobalt, ruthenium, nitrides thereof, alloys thereof,combinations thereof, or the like. The thickness of the conformal metallayer is not intended to be limited and is generally between 100Angstroms and 5000 Angstroms. A patterning process can be followed todefine area and structure of the capacitor element (not shown).

In FIG. 6, an intermetal dielectric layer 26, also referred to as aninterlayer dielectric layer, is deposited onto the substrate 10. Thedielectric layer, 26 can be any dielectric material including inorganicdielectrics or organic dielectrics. The dielectric material can beporous or non-porous. Some examples of suitable dielectrics that can beused as the dielectric material include, but are not limited to: SiO₂,silsesquioxanes, carbon doped oxides (i.e., organosilicates) thatinclude atoms of Si, C, O and H, thermosetting polyarylene ethers, ormultilayers thereof. The term “polyarylene” is used to denote arylmoieties or inertly substituted aryl moieties which are linked togetherby bonds, fused rings, or inert linking groups such as, for example,oxygen, sulfur, sulfone, sulfoxide, carbonyl and the like. Thedielectric layer can be deposited by plasma enhanced chemical vapordeposition procedures as is generally known in the art. The thickness ofthe dielectric layer 26 generally ranges from 50 nm to 5000 nm, althoughlesser and greater thicknesses can also be employed.

IN FIG. 7, the substrate 10 is subjected to a planarization process suchas electropolishing, chemical mechanical polishing or the like. Theplanarization process is to the top surface of the metal 12 and definesthe vertical MIM capacitor structure, which generally includes trenchsidewall of the metal and metal liner 12, 18, the high k dielectric 22,and the patterned metal 24.

In FIG. 8, interconnection of the metal level, i.e., conductor, with aninterconnect structure is made. A capping layer 30 is formed on theplanar surface of the substrate 10 and the interconnect structure to themetal conductor 12 can be formed. The capping layer 30 protects theunderlying metal conductive line 112 from oxidation, humidity, andcontamination during formation of the interconnect structure and thenext metal level(s) on the semiconductor substrate 10. Additionally,capping layer 30 serves to prevent undesirable diffusion of theunderlying conductor 12 into interlayer 34. Capping layer 30 can be madeof any suitable capping material such as silicon nitride, siliconcarbide, silicon oxycarbide, hydrogenated silicon carbide, silicondioxide, organosilicate glass, and other low-k dielectrics.

The process for forming the interconnect structures generally beginswith formation of an interlayer dielectric 34 onto the capping layer 30,wherein formation of the interlayer 34 includes deposition of one ormore dielectric layers.

The interlayer dielectric 34 can be any dielectric material includinginorganic dielectrics or organic dielectrics. The dielectric materialcan be porous or non-porous. Some examples of suitable dielectrics thatcan be used as the dielectric material include, but are not limited to:SiO₂, silsesquioxanes, carbon doped oxides (i.e., organosilicates) thatinclude atoms of Si, C, O and H, thermosetting polyarylene ethers, ormultilayers thereof. The term “polyarylene” is used to denote arylmoieties or inertly substituted aryl moieties which are linked togetherby bonds, fused rings, or inert linking groups such as, for example,oxygen, sulfur, sulfone, sulfoxide, carbonyl and the like. Thedielectric layer can be deposited by PECVD, spin-on or other proceduresas is generally known in the art.

The process then includes patterning the interlayer 34 using standardlithography and etching techniques. The lithographic step generallyincludes applying a photoresist to the surface of the dielectric layer,exposing the photoresist to a desired pattern of radiation, anddeveloping the exposed resist utilizing a photoresist developer to forma pattern. The etching process can be a dry etching or wet etchingprocess. The capping layer 30 at the bottom of the via 31 is alsoselectively removed, thereby exposing the metal conductive line 12 aswell as the metal layer 24.

A plasma treatment can then be performed to clean the exposed thesurface of the metal conductive line 12 at the bottom of the via 31 ofcontaminants, oxides, nitrides, or the like. The plasma cleaning stepcan include exposing a process gas including H₂, He, forming gas, O₂ orcombinations thereof and a carrier gas. The carrier gases can includeinert gases such as He, Ne, Ar, Kr, Xe and Rn, and combinations thereof.The process conditions can include a temperature of between about roomtemperature and about 450° C., a pressure of between about 0.5 mtorr andabout 100 torr, an ion current density generally less than 50 μA/cm²,and a process time of between about 5 seconds and about 600 seconds. Inone or more embodiments, the ion current density is about 5 to about 20μA/cm². The cleaning step can be repeated multiple times as desired.

Metallization of the via 31 is completed by deposition of a metal linerlayer onto the substrate followed by metal filling 32 and chemicalmechanical planarization so as to form the semiconductor structure as isgenerally shown in FIG. 8.

The metal liner layer can be deposited onto the exposed dielectricsurfaces by a deposition process such as, for example, PVD, atomic layerdeposition (ALD), chemical vapor deposition (CVD), plasma enhancedchemical vapor deposition (PECVD), sputtering, chemical solutiondeposition, or plating. The thickness of metal liner layer generallyranges from 0.5 Angstroms to 250 Angstroms. The resulting metal linerlayer serves as a barrier to prevent the subsequently deposited metalconductive interconnect material from diffusing through to thedielectric layer 34.

The metal lined via features are then filled with a conductive metalsuch as copper to form the interconnect structure 32. Filling thepattern with a copper metal can include first depositing a copper seedlayer. The copper seed layer can be also deposited by sputtering. Theseed layer would typically be about 50 to 400 Å thick. The function ofthe seed layer is to provide a base onto which a main conductor layercan be deposited. The seed layer can be deposited by atomic layerdeposition (ALD), sputter deposition, plasma vapor deposition (PVD),chemical vapor deposition (CVD) or the like.

Suitable seed layers are generally chosen to provide improvedelectromigration resistance, improved adhesion to the underlying linerlayer, and improved surface properties suitable for deposition of themain conductor copper body. Exemplary copper alloys that have been shownto improve the electromigration resistance relative to pure copper,include Cu (Sn), Cu (In), Cu (zr), Cu (Ti) and Cu (C, N, O, Cl, S).Exemplary seed layers that improve the adhesion properties relative topure copper which include Cu (Al), Cu (Mg), and alloys of Cu with otherreactive metals such as Be, Ca, Sr, Ba, Sc, Y, La, and rare earth serieselements of Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, andHf, V, Mb, Ta, Cr, Mo, W, Mn, Re, Si and Ge. The seed layer can includeadditional alloying elements that improve surface properties for theseed layer such as B, O, N, P, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Ag,Au, Zn and Cd. Uniformity of seed layer is typically desired, because apoor seed layer can result in voids. It is also desirable to ensure thatthe seed layer surface is free of oxides for efficient charge transferduring plating.

On top of seed layer, a conductive metal layer (e.g., a copperconductor) is deposited. The conductive metal layer can be depositedonto the surface by an electrochemical deposition process. Otherprocesses such as e-beam evaporative deposition, physical vapordeposition, or CVD, can be used to deposit the metal layer. Theconductive metal fills the via trench features. In addition, a metaloverburden layer is formed over the top surfaces of the dielectriclayer, which is also referred to as the overburden. Exemplary conductivemetals suitable for the interconnect structure includes low resistivitymaterials such as copper, aluminum, tungsten, cobalt, ruthenium,iridium, rhodium, mixtures thereof and the like.

In one or more embodiments, the substrate is then subjected to anannealing process, which improves various properties of the metalconductor such as providing an increased grain size so as to increaseconductivity, reducing stress, and reducing electromigration. Theannealing process generally includes heating the substrate at anelevated temperature typically less than 400° C. in an inert atmospherefor a defined period of time of about sixty minutes or less. Ovens,furnaces, rapid thermal processing equipment and the like can beutilized for the annealing process.

After annealing, a chemical mechanical polishing (CMP) process is thenutilized to remove the overburden and portions of the liner layer 124formed at the top surface of the dielectric layer 34, i.e., removesmaterial from the field area. The CMP process planarizes the surface ofthe interconnect structure by a combination of chemical and mechanicalforces generally known in the art. By way of example, CMP can removematerial through the physical grinding of a slurry containing abrasiveparticles such as silica, as well as through chemical action as a resultof oxidizing agents such as hydrogen peroxide contained in the slurry.The trench feature in the resulting interconnect structure includes aliner layer formed within the dielectric layer, the seed layer, and themetal conductor. Optionally, the CMP process can occur prior to theannealing process.

It should be apparent that the resulting vertical MIM capacitorstructure is located within one patterned feature and includes twovertical electrodes and an insulator therebetween. One of the electrodescontains two different metallic layers, e.g., the metal conductor andmetal liner whereas the other electrode contains a single metalliclayer. The process is compatible with current BEOL process flows.

All ranges described herein are inclusive of the endpoints, and theendpoints are combinable with each other.

All cited patents, patent applications, and other references areincorporated herein by reference in their entirety.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. Further, it should further be noted that the terms “first,”“second,” and the like herein do not denote any order, quantity, orimportance, but rather are used to distinguish one element from another.

While the present invention has been described in terms of specificembodiments, it is evident in view of the foregoing description thatnumerous alternatives, modifications and variations will be apparent tothose skilled in the art. Each of the various embodiments of the presentinvention can be implemented alone, or in combination with any otherembodiments of the present invention unless expressly describedotherwise or otherwise impossible as would be known to one of ordinaryskill in the art. Accordingly, the present invention is intended toencompass all such alternatives, modifications and variations which fallwithin the scope and spirit of the present invention and the followingclaims.

What is claimed is:
 1. A method for forming a verticalmetal-insulator-metal capacitor, the method comprising: providing asemiconductor substrate comprising a patterned insulator layer includinga metal conductor formed in the patterned insulator layer, wherein a topsurface of the patterned insulator layer is coplanar to a top surface ofthe metal conductor; selectively depositing a metal cap layer onto thetop surface of the metal conductor; removing the patterned insulatorlayer surrounding the metal conductor; selectively depositing a high kdielectric material onto a sidewall of the metal conductor; conformallydepositing a metal plate layer onto the semiconductor substrate;depositing a second insulator layer onto the semiconductor substrate;planarizing the semiconductor substrate to the top surface of the metalconductor, wherein the metal conductor sidewall and the high kdielectric material are vertically oriented, and the metal plate layerincludes vertically oriented and horizontally oriented portions; forminga capping layer on the planar surface of the semiconductor substrate;forming an interlayer dielectric onto the capping layer; filling a firstvia to the metal conductor with a metal, wherein the metal conductordefines a first electrode; forming filling a second via to a horizontaloriented portion of the metal plate with a metal, wherein the metalplate defines a second electrode.
 2. The method of claim 1 furthercomprising forming an upper level interconnect and creating electricalcontacts to both the metal conductor and the metal cap layer.
 3. Themethod of claim 1, wherein removing the patterned insulator layersurrounding the metal conductor comprises a wet etch process.
 4. Themethod of claim 1, wherein the selectively depositing the metal caplayer onto the top surface of the metal conductor comprises chemicalvapor deposition or atomic layer deposition.
 5. The method of claim 1,wherein the high k dielectric comprises tantalum oxide, barium strontiumtitanate, strontium titanate, barium titanate, lead zirconium titanate,silicon carbide, silicon oxynitride, silicon nitride, zirconium oxide,aluminum oxide, hafnium oxide, or strontium bismuth tantalate.
 6. Themethod of claim 1, wherein the metal conductor and the metal plate layerare different metals.
 7. The method of claim 1, wherein the metalconductor comprises a metal and a metal liner layer, and the metal platelayer is a single metallic layer.
 8. The method of claim 1, wherein themetal conductor comprises copper, aluminum, tungsten, ruthenium,iridium, rhodium, cobalt, or mixtures thereof.
 9. A method for forming avertical metal-insulator-metal capacitor, the method comprising:providing a semiconductor substrate comprising a patterned insulatorlayer including a metal conductor formed in the patterned insulatorlayer, wherein a top surface of the patterned insulator layer iscoplanar to a top surface of the metal conductor; blanket depositing adielectric cap layer onto coplanar top surfaces of the metal conductorand the patterned insulator layer; patterning the dielectric cap layerto expose the top surface of the patterned insulator layer; removing theexposed patterned insulator layer surrounding the metal conductor;selectively depositing a high k dielectric material onto a sidewall ofthe metal conductor; conformally depositing a metal plate layer onto thesemiconductor substrate; depositing a second insulator layer onto thesemiconductor substrate; planarizing the semiconductor substrate to thetop surface of the metal conductor, wherein the metal conductorsidewall, the high k dielectric material and the metal plate layer arevertically oriented and define the vertical MIM capacitor.
 10. Themethod of claim 9 further comprising forming an upper level interconnectand creating electrical contacts to the metal conductor.
 11. The methodof claim 9, wherein the high k dielectric comprises tantalum oxide,barium strontium titanate, strontium titanate, barium titanate, leadzirconium titanate, silicon carbide, silicon oxynitride, siliconnitride, zirconium oxide, aluminum oxide, hafnium oxide, or strontiumbismuth tantalate.
 12. The method of claim 9, wherein the metalconductor and the metal plate layer are different materials.
 13. Themethod of claim 9, wherein the metal conductor comprises a metal and ametal liner layer, and the metal plate layer is a single metallic layer.14. The method of claim 9, wherein the metal conductor comprises copper,aluminum, tungsten, ruthenium, iridium, rhodium, cobalt, or mixturesthereof.